Apparatus for producing artificial fog or smoke



Dec. 5, 1944. T. s. DERR 2,364,199

APPARATUS FOR PRODUCING ARTIFICIAL FOG 0R SMOKE Filed Jan. 18, 1943Patented Dec. 5, 1944 APPARATUS FOR PRODUCING ARTIFICIAL FOG OR SMOKEThomas S. Derr, Newton, Mass.,

American Steam Automobile Company,

assignor to West Newton, -Mass., acorporation of MassachusettsApplication January 18, 1943, Serial No. 472,725

3 Claims.

This invention relates to the production of an artificial fog or smokefor use as a screen or any other purpose, and the principal objects areto provide a method of and means for producing a fog or smoke rapidly,extensively and at a relatlvely low cost, without risk of fire orexplosion and with material which is inexpensive and readily availableand which is non-injurious to man and equipment, to start the productionof a fog or smoke on short notice, and to produce a fog or smoke of anydesired color and quickly to change the color thereof.

Further objects will be apparent from a consideration of the followingdescription and accompanying drawing, wherein the figure is alongitudinal section through what is now considered a preferred form ofthe apparatus.

According to the present invention the fog or smoke-producing apparatuscomprises a series of interconnected nozzles or the like conduitsarranged so that each successively discharges into the next succeedingnozzle which is of sufliciently greater size or cross-sectional area tocreate a zone of reduced pressure separated from the body of the mainjet by a zone of turbulence; and each nozzle after the first one isprovided with an inlet opening arranged to communicate with the zone ofreduced pressure so as to provide an aspirator effect. One or more ofthe inlet openings may be connected with a supply reservoir or hopper ofthe material to be dispersed, and one or more of the other inletopenings may be connected with a suitable source of a gaseous diluentsuch as air, hot flue gases, or the like.

The material to be dispersed may comprise either a high boiling pointfluid or a finely divided solid, such, for example, as clay, dependingupon whether a fog or smoke is to be produced, the desired effects. etc.Clay and the like naturally occurring mineral substances are preferredin that such material is readily available, inexpensive, non-injuriousand capable of being easily reduced to a flne state of subdivision. Inany case a gaseous fluid such as compressed air or steam, preferablysuperheated, is discharged through the first nozzle so as not only tocreate a zone of decreased pressure which aspirates either the gaseousdiluent or the material to be dispersed through the inlet opening of thesecond nozzle, but also sets up a zone of turbulence eflective to breakup or disintegrate the aspirated material and entrain it into the mainjet which travels through the second nozzle at a relatively highvelocity. The same performance is repeated when the jet of the secondnozzle discharges into the third nozzle and so on until the last of theseries of nozzles discharges into the atmosphere.

The arrangement of the inlet openings for the diluent gases and thematerial to be dispersed may be varied and will depend upon thecharacter of the material to be dispersed, the particular type of gas orgaseous fluid discharged by the first nozzle and the diluent gas orgasesadmitted to the other nozzles, and various other factors which willbe recognized by those skilled in the art. Although the diluent gas maybe aspirated as above noted, other inlets may be provided through whichdiluent gas may be introduced either under a pressure greater than thatwithin the nozzle provided with such inlets, or by blowing the gas in ata suitable velocity. If desired, a plurality of supply hoppers, eachcontaining a different colored dispersible material, may be connected toone or more of the inlet openings so that any desired color effects maybe produced and valves or the like control means may be provided foreach inlet opening so that the density of the smoke or fog may beadjusted or varied as desired.

The embodiment herein shown for the purpose of illustration comprises aseries of interconnected axially aligned nozzles I, 2, 3 and 4 arrangedso that nozzle l discharges into the adjacent end of nozzle 2, the saidadjacent end of said nozzle 2 being of greater cross-sectional area thanthe discharge end of nozzle l; and nozzle 2 likewise discharges into thenozzle 3 which is of greater cross-sectional area than nozzle 2, etc.Although the dimensional relationship of the nozzles may vary,satisfactory results have been obtained using a nozzle I having a boreof the order of /4" and flaring to about a nozzle 2 having a bore of theorder of 1"; a nozzle 3 having a bore of the order of 1 /2"; and anozzle 4 having a bore of the order of 2" which may or may not flareoutwardly. In any case the size of the discharge end of nozzles I to 3should be sufficiently smaller with respect to the inlet ends of nozzles2 to.4, respectively, so that a jet, indicated by the straight arrows'5,creates a zone of reduced pressure, indicated by stippling 6, which isseparated from the main jet 5 by a zone of turbulence, indicated by thecurved arrows I.

The nozzles 2, 3 and 4 are provided with inlet openings H], II and I2,respectively, each communicating with a zone 5 of reduced pressure, andthe inlets are selectively connected by suitable duets with a source ofthe material to be dispersed and a diluent gas. Where, for example. thenozzle I is connected with a-supply or superheated steam, for exampleunder a pressure of the order of 250 pounds per square inch, and

hot flue gases are to be used as a diluent, the inlets lll and I! areconnected by ducts l4 and II with a supplyof flue gas and the inlet IIis connected to a supply duct it formed with a funnel-like end' I! whichreceives the conical end I! or a supply hopper 20, the walls or the endsl1 and! being spaced to provide a gap is so arranged as to provide anaspirator effect. If desired suitable valves 2|, 22, 23 and 24 may beprovided to control the flow through the nozzle I and inlets I0, H andI2, respectively.

In order to operate the apparatus to produce an artificial fog or smokethe hopper 20 is first supplied with a dispersible solid material of the'desired color, such for example as clay or the like material, and withthe valves 22 to 24 properly adjusted, the valve 2| may then be openedto discharge a jet 5 of superheated steam or other gaseous fluid intothe nozzle 2, thereby creating a zone 6 of reduced pressure and a. zoneI of turbulence. The zone of reduced pressure is effective to draw inthrough the inlet l hot flue gases, or other diluent, which areentrained with the main jet 5.

Under some conditions the diluent gas entering through opening l0 servesalso to increase the capacity or efliciency of the apparatus by enablinga fixed amount of high pressure gaseous fluid to disperse more materialthan would be feasible if the jet of high pressure gaseous fluid acteddirectly on the material; in other words, the diluent gas enteringthrough opening l0, under some conditions, makes possible an increase incapacity to disperse material, over what would be the case if the jetdischarged from nozzle I acted directly on the material without thebenefit of the diluent gas.

The jet travels through the nozzle 2 and discharges into the nozzle 3and a similar action takes place. However, at this stage the jetaspirates the material to be dispersed through opening II and the zoneof turbulence 1 is efiective to break up or pulverize this material sothat as it is entrained by the main jet 5 it becomes entirely or almostentirely dispersed therein. As the material in the hopper 20 is drawnthrough the conduit l6, air is also drawn in through thegap I 9 whichnot only helps to regulate the flow of material through duct IE, butalso tends to prevent clogging and thus, tends to efiect a more uniformintroduction of the materialinto the nozzle 3 s As the jet 5 and itsentrained material is discharged into the nozzle 4, more hot flue gases,or other suitable diluent, are aspirated through the opening l2 andthese hot gases, or other suitable diluent, not only act to reduce orprevent condensation of the steam upon its emergence into the atmosphere(it steam is used), but also serve to create a greater degree ofturbulence within the nozzle 4 than would otherwise occur, and hence areeffective to improve the quality of the fog or smoke in that theparticles of dispersed material are more thoroughly broken up and moreuniformly distributed throughout the moving mass of gas. Finally the jet5 is discharged from the end of nozzle 4 into the atmosphere to form asmoke cloud, the density and volume of which may be varied by properadjustment of the valves 2| to 24 and the color of which may be variedor changed by introducing an appropriately colored material through theduct "5 into nozzle 3,

With the aforesaid sizes of nozzles and a steam pressure of the order of250 pounds per square inch and a steam temperature of 600 F. to 700 F.,the steam flow being of the order of eight pounds per minute, thisapparatus will disperse a fine powdered clay such as bentonite at therate of ten to fifteen pounds per minute; and on a, relatively calm daythe apparatus will generate fog at a sufliciently rapid rate to obscureone-half acre to one acre per minute.

While I have shown and described one desirable embodiment of theinvention, it is to be understood that this disclosure is for thepurpose of illustration and various changes and modifications may bemade without departing from the spirit and scope of the invention as setforth in the appended claims.

I claim:

1. Apparatus for producing an artificial fog or smoke comprising aseries of at least three interconnected nozzles, the second, and thirdnozzles being of greater cross-sectional area respectively than thefirst and second nozzles of the series so that a Jet of gaseous fluiddischarging from one nozzle into the next nozzle creates a zone ofdecreased pressure separated from the main jet by a zone of turbulence,the second, and" third nozzles having inlets communicating with thezones of decreased pressure, means for introducing a dispersible.material through one of the inlets, and means for introducing gaseousdiluent through another of said inlets.

2. Apparatus for producing artificial fog or smoke comprising a seriesof interconnected nozzles arranged so that one discharges into the nextof the series, each nozzle receiving the jet discharged from thepreceding nozzle being of greater cross-sectional area so that upon thedischarge of the jet there is created a zone of decreased pressureseparated from the main jet by a zone of turbulence, each of thejet-receiving nozzles being provided with an inlet communicating withthe zone of decreased pressure, and supply ducts connected with saidinlets for selectively introducing dispersible material and a gaseousdiluent into the zones of decreased pressure.

3. Apparatus for producing artificial fog or smoke comprising a seriesof interconnected nozzles arranged so that one discharges into the nextof the series, each nozzle receiving the jet discharged from thepreceding nozzle being of greater cross-sectional area so that upon thedischarge of the jet there is created a zone of decreased pressureseparated from the main jet by a zone of turbulence, each of thejet-receiving nozzles being provided with an inlet communicating withthe zone of decreased pressure, a supply hopper for receivingdispersible material connected to one of said inlets, and a duct forintroducing gaseous diluent connected to another of saidinlets.

THOMAS S. DERR.

